The desire to improve the image quality of printed output produced by inkjet printing systems has led to the development of printheads with increased densities of liquid ejection elements, typically characterized in nozzles-per-inch. These liquid ejection elements controllably emit a number of drops of a given color liquid onto a particular location of a print medium that corresponds to a particular portion, such as a pixel, of an image being printed. Along with the desire for improved image quality often comes the desire for higher printing throughput, in order to reduce the time needed to produce the printed output. One technique for increasing throughput is to deposit all of the drops of the given color liquid on the particular location from a single liquid ejection element in a single printing pass of the ejection element and the print medium relative to each other.
However, difficulties in fabricating printheads with high ejection element densities may lead to low manufacturing yields for printheads capable of producing the high image quality desired. In turn, this low yield results in high printhead costs and prices. In addition, over time the printing characteristics of some of the ejection elements may degrade with usage. If the degradation in image quality reaches an unacceptable level, printhead replacement is performed, at additional cost and effort to the user.